The present invention relates to container constructions formed from blanks of sheet material, e.g., corrugated fiberboard and the like, and particularly to so-called cornerpost-style trays and boxes including corner reinforcement structures serving to increase container stacking strength and stability.
A variety of containers incorporating corner reinforcing structures are known. A particularly prevalent corner reinforcement configuration, used in trays and other types of containers, comprises a post structure formed from a corner flap extending laterally from the opposite ends of a container wall panel. The corner flap includes a pair of spaced score lines, in addition to a score line attaching the corner flap to the wall panel, demarcating a series of three corner panels. The corner flap is folded-back onto an inside surface of the wall panel and secured thereto, to thereby form (in conjunction with a corner portion of the wall panel) a tubular cornerpost configuration of triangular shape. An adjacent orthogonal wall panel (e.g., end wall or sidewall), folded-up from a floor of the container may be secured to an outer planar surface of the triangular cornerpost structure. Such a conventional construction is exemplified by the container disclosed in Parks U.S. Pat. No. 1,653,116, and is schematically illustrated in prior art FIG. 1.
As shown in FIG. 1, a conventional cornerpost-style tray comprises pairs of opposing sidewalls 1 and endwalls 3 folded-up from a floor panel (not shown). A plurality of corner panels 5a, 5b and 5c are attached along opposite lateral edges of each endwall 3. The corner panels are doubled-back onto an interior side of sidewall 3 to thereby form respective corner post structures 5 to which orthogonal sidewalls 1 are secured. The circular dots in FIG. 1 show where glue is typically applied to secure sidewalls 1 to each cornerpost structure 5, and to secure outermost corner panel 5c to the inside surface of endwall 3.
Numerous variations on this basic construction are known.
Ferguson U.S. Pat. No. 2,299,812 discloses triangular cornerpost members formed from pieces separate from the main box-forming blank, and secured by a hook structure of the box blank.
Guyer U.S. Pat. No. 2,885,140 discloses a diagonal cornerpost structure including, as shown in FIG. 8 thereof, a strap-like locking tab extending across the inside diagonal surface of each triangular post.
Adams U.S. Pat. No. 3,397,831 discloses cornerpost structures and wall reinforcements formed by separate pieces of material secured to a main box forming blank.
Garza U.S. Pat. Nos. 5,535,941 and 5,673,848 disclose triangular cornerpost structures with adjacent reinforcing panels.
Arnold U.S. Pat. No. 1,085,188 discloses a container with panels that fold over to form diagonal corner members. Specifically, blank sections fold over into overlapping relationship with adjacent end sections. The blank sections include wings which form, in a folded-over condition, diagonally extending partial-height corner pieces fitted within corresponding wall panel cut-outs.